Deadwood is a habitat for numerous biota and serves as an indicator of forest biodiversity. Bryophytes significantly contribute to deadwood communities and epixylic bryophytes are particularly threatened. Additional to deadwood volumes, their occurrence depends on climatic conditions. However, the interactive effects of deadwood and climate on epixylic bryophytes have hardly been assessed. Here, we analyse these effects based on 8 143 bryophyte specimens collected on 510 logs in 51 Austrian forests. We found that annual precipitation sum and deadwood volume explained 67%, 90%, and 82% of the variation in moss, liverwort and total species richness, respectively. Segmented regression indicated several breakpoints in these relationships, especially at c. 60 m³/ha of deadwood and 900 mm, respectively 1700 mm of annual precipitation. Epixylic bryophyte diversity increased strongly up to the deadwood threshold, but only moderately with still higher volumes. Nine hundred mm of annual precipitation was a macroclimatic limit for deadwood-specific bryophyte species. Below this value, obligate epixylic bryophytes were lost and liverworts were rare, even at sites with high deadwood amounts. At the wettest sites, the overall number of species decreased while deadwood-specific specialists further increased in number. The close tie of epixylic bryophytes to macroclimate may constrain the efficiency of deadwood management measures and suggests considerable impacts of climate change. A drier and warmer climate will probably decrease species richness and change the composition of epixylic bryophyte communities, with the most characteristic species, especially liverworts, facing the highest risk.

枯木是众多生物群落的栖息地，可作为森林生物多样性的指标。苔藓植物极大地促进了枯木群落，表生苔藓植物尤其受到威胁。除沉木量外，它们的发生还取决于气候条件。但是，几乎没有评估沉木和气候对表生苔藓植物的相互作用。在这里，我们基于在51个奥地利森林的510块原木上采集的8 143个苔藓植物标本分析了这些影响。我们发现，年降水量和枯木量分别解释了苔藓，地艾和总物种丰富度变化的67％，90％和82％。分段回归表明这些关系中有几个断点，尤其是在c处。60 m ³每公顷的枯木和900毫米的年降水量，分别为1700毫米。表生苔藓植物的多样性在达到枯木阈值之前迅速增加，但仅适度增加。900毫米的年降水量是特定于枯木苔藓植物的宏观气候极限。低于该值，即使在枯木含量高的地方，专性表生苔藓植物也会丢失，且艾蒿很少见。在最潮湿的地方，物种总数减少了，而枯木专用专家的数量进一步增加了。表生苔藓植物与大气候的紧密联系可能会限制枯木管理措施的效率，并暗示气候变化的巨大影响。更干燥，更温暖的气候可能会降低物种的丰富度并改变表观苔藓植物群落的组成，